Slide tuner



April 26, 1960 c. E. LYON, JR

SLIDE TUNER 2 Sheets-Sheet 1 Filed Sept. 11, 1958 ill] II/ Ill 40 Jill/lA fizz/2712407:

April 26, 1960 c. E. LYON,.JR 2,933,927

SLIDE TUNER Filed Sept. 11, 1958 2 Sheets-Sheet 2 are quite complex andrelatively costly.

positively and which requires "lateral movement to a locks the same bymovement of the actuating portion of when the worm screw is SLIDE TUNER"CharlesjE. Lyon, Jr., Motorola, Inc., Illinois Application September11, .1958, Serial No. 760,325

lo Claims. (CL 74-1037) Des Plaines, Ill., assignor to Chicago, Ill., acorporation of This invention relates generally to tuning apparatus forradio receivers,-and more particularly to a'tuner'for automobileradioreceivers having a pushbutton operating mechanism which maybereadilypreset to select predetermined frequencies within a frequencyrange, and having a continuous operating mechanism for manual tuningthroughout-the frequency range.

United States v Patent;

Tunershaving pushbuttons for automatic tuning are commonly provided witha mechanism which may be adjusted to set up the predeterminedfrequencies for auto matic selection. Known tuners of this type aresomewhat bulky and, therefore, are not ideally suited for use radioswhich must be small because of Some known conso that the averageautomatic stations conveniently. Constructions which may be set upeasily Accordingly, it is an object of this invention to pro- -vide atunerforautomobile radio receivers which is substantially reduced insize and which may be mass produced at low cost.

Another object of the invention is to provide a pushbutton tuner with asimple adjustment mechanism for setting up automatic stations whichoperates easily and few component parts.

A feature of the invention is the provision of a small and compact tunerfor a radio receiver including a plurality of movable key slides havingadjustable pins which are located in predetermined control positionswith respect to V-shaped cam surfaces on a core carriage, and which are'engageable with these cam surfaces upon movement of the respective keyslides to move the core .carriage to-predetermined tuning positions.

Another feature of the invention is the provision of key 'slideshavinglaterally movable pins for cooperation with the V-shaped cams asdescribed above, and a quick- .release locking construction which freesthe pins for new control position and then theslide.

A further feature of the invention is the 'provisionof a tuner asdescribed above including a compact con- "tinuous tuning mechanismhaving a worm screw and a "meshing-worm gear connected core carriage, sothat the worm gear rotates and walks by a friction clutch to the alongthe worm screw when the carriage is moved by the key slides but remainsrotationally fixed and follows the threads of the worm screw to move thecore carriage rotated by a manual tuning shaft.

The invention is illustrated in the accompanying drawings in which: 7

Fig. '1 is a top view in longitudinal section of a tuner .in accordancewith the invention;

I Jfig. '2 isa front view vof the tuner of Fig. .1 with the .key slidein the unlocked carriage during continuous operation. slides areoperated, the friction clutch slips and permits .the Worm gear to rotateand walk along the worm screw "locking lever which guided in slots 17provided 2,933,927 Patented Apr. 26,1960

front plate broken away to reveal the internal mechanism;

Fig. 3 is an end view in transverse section of the tuner of Fig. 1;

Fig. 4 is a detail view of one of the key slides of the tumor of Figs.1--3; and

Fig. 5 is a detail view similar to Fig. 4 showing'the condition.

In' practicing the invention there is provided a tuner having anautomatic control mechanism including a longitudinally movable corecarriage having a pluralitytof V-shaped cam surfaces and a plurality ofkey slides mov- :ablev laterally with respect'to the carriageandeachhavmg an adjustable pin which is-engageable with 'one of the camsurfaces to move the carriage to a predetermined tuning position.Acontinuous control mechanism :15 provided including a worm screw and ameshing worm gear which is held rotationally fixed by a friction clutchand follows the threads of the worm screw to-move the When the key asthe core carriage moves, so that it is not necessary to provide parts touncouple the continuouscontrol during automatic operation. Thecontinuous control mechanism is very compact and cooperates with theautomatic control mechanism in a manner which permits a substantialreduction in the size of the tuner. In normal operation the adjustablepins of the key slides are held in place by a quick-release lockmechanism including a is forced against the pin by an actuating portionof the key slide.

frees the pin for lateral movement on the slide. When the key slide isthen depressed, the movable pin engages the V-cam and follows itssloping cam surface to the base of the V. Further pressure on the keyslide moves and an end portion 49 which supports four cores 51 inalignment with four tuning coils 52 contained in a coil housing 53. Partof the housing 53 is broken away in Fig. 1 to give a better viewof thecore carriage 40. 'The tuning coils 52 are connected to terminals 54mounted on the housing 53, and the terminals 54 may be wired into thetuning circuits of a radio receiver. The cores 51 arermoved'in and outof the coils 52 upon longitudinal movement of the core carriage 40, andthe position of the cores with respect to the coils determines the'frequency of the radio signals picked up and reproduced by theassociated receiver.

The core carriage 40 may be moved to presettuning positions toselectradio signals of predetermined frequencies by operation of an automaticcontrol mechanism including a plurality of key slides 2126'which aredisposed in two rows on the frame 11 and which are actuated to engagethe V-cams 41-46 by depressing the pushbuttons 29. The key slides eachinclude a slide portion 27, and a key portion 28 which is normallylocked in a fixed position with respect to the slide. The edges of theslide members 27 fit into notches 56 provided in When the actuatingportion is pulled out, the locking lever is released, and this 59 whichengage the front plate 12 to define the initial position of the keyslides. Coil springs 61 (Fig. 3) may be attached to the front plate 12and to the bent-over ear 62'on the slide member 27 to return the keyslides to their initial position when they are released.

The key slides 2126 are respectively provided with pins 31-36 which areengageable with V-shaped cam surfaces 4-1-46 formed in the channelportions 47 of the core carriage 40. The pins 31-36 are normally lockedin place on the key slides by a locking mechanism which will beexplained later, but it may be noted at this point that thepins aremovable along the slots 37 laterally with respect to the key slides todifferent control positions. The spacing between the centers of theslots 37 is the same as the spacing between the bases 50 ofthe V-cams41-46, so the condition where the centers of slots 37 and the bases 50are aligned as illustrated is a convenient reference position. Theamount the pins are offset from the centers of their guide slots 37controls the displacement of the carriage 40 from this referenceposition when any one of the key slides is actuated.

The automatic operation may be understood most clearly from aconsideration of Fig. 1. The key slide 21 is shown in the fullydepressed position with the pin 31 engaging both sides of the V-cam 41adjacent the base 50. It may be noted that the base 50 is slightlynarrower than the diameter of pin 31 to ensure that the pinchgages bothsides of the cam surface in the fully depressed position, and thispositively locates the core carriage. The position of the cores 51 withrespect to the coils 52 controls the inductance value of the tuningcircuits of the associated radio receiver and, there- .fore selects aradio signal of a particular frequency. If

it is desired to tune in a signal of another frequency, the key slide23, for example, may be pushed in. When the pin 33 engages the camsurface 43, the carriage 40 will be moved to the right and the pin 33will follow the right side of surface 43 as the slide is depressedfurther until the pin reaches the base 50. The sides of the cam surfacesare slightly curved so that as the pin moves along the 'side, thedirection of the resultant force acting on the carriage varies. Thecurvature is convex so that as the lateral distance between the pin 33and the base 50 decreases, less actuating force is required to move thecarriage. This controls the touch or feel of the pushbuttons and helpsto make the keyslides operate smoothly. The cores 51 move into the coils52 changing the inductance value in the tuning circuits of the receiverand selecting a new station. The core carriage 40 is held in theselected position by the resistance of the gear train associated withthe continuous control mechanism 19 which will be explained later. Adial mechanism 13 including a pointer 63 on a pivotal arm 64rnovesacross the face of a dial panel 65 to give a visual indication of thestation which has been selected. The arm 64 is connected to a supportbracket 66 by a pin'67 which is slidable in a slot 68, and its movement.is controlled by a link 69 pivotally connected to arm 64 at one end andpivotally connected to the support 66 at the other end.

In order to change the station or radio signal which is set up-forselection by any one of the key slides, the pin of the key slide may bemoved to a new control position. This operation may be understood byconsidering Figs. 1, 4 and together. The key slide 23 is shown in detailin Figs. 4 and 5 to illustrate the locking construction which holds thepin 33 in place and which may bequickly released to free the pin foradjustment. It may be seen that both the slide member 27 and the key 28are plates and that the pin 33 has an enlarged base portion 38 betweenthe plates which is held tightly against the slide 27 adjacent the slot37 by a locking lever 71. The lever '71 is supported at both "ends inopenings which are cut out of the bent-over -leg anama? c portions 81and 82 of the slide 27. The opening in leg 82 is large enough to permitpivotal movement of the lever. The lever 71 has a bump 72 which engagesanother hump 73 in the plate 28 when the key slide is in the lockedcondition, and the hump portions 72 and 73 apply resilient pressure tothe lever 71 so that raised surface 74 is forced firmly against the pin33 to hold it in place. They key 28 is movable with respect to the slide27 between the locked position shown in Fig. 4 where the tongue 75 abutsone end of the opening 76, and an unlocked position shown in Fig. 5where the bent end 78 of key 28 engages leg 82. To unlock the pin 33 thekey 28 is pulled out, and the hump 73 in the key 28 slides out fromunderneath the hump 72 in the locking lever 71. This permits the lever71 to move away from the pin 33 under pressure applied by the leafspring 83. The station which is to be set up for selection by the keyslide 23 is tuned in by operating thecontinuous control 19. The keyslide 23 is then pushed in, and the pin 33 engages cam surface 43 and ismoved along slot 37 as it follows surface 43 to the base 50 of theV-cam. The pin 33 is now positioned to provide automatic selection ofthe desired station and may be locked in place. This is accomplished bypushing harder on the button 29 so that the key 28 moves with respect toslide 27 to engage the bumps 72 and 73 and force lever 71 against .thepin 33; It may be noted that during the first portion of the movement ofthe key slide, the members 27 and 28 move together and not relativelybecause of the resistance between the humps 72 and 73 and also becauseof the resistance between the hump 77 and the leg 81. .When the keyslide 23 is in the fully depressed position, increased force must beapplied to overcome these resistances and move the key 28 to the rightrelative to the slide 27 as illustrated.

The continuous control mechanism, designated generally as 19, will beexplained with reference to Figs. .1'-

Rotation of the knob 84 turns the shaft 85 and rotates the crown gear 86on the end of the shaft. A pinion gear 87 meshes with the crown gear 86and this rotates the worm screw 91. A worm gear 92 meshes with the wormscrew 91 and is afiixed to a shaft 93 which also has a disc 94 offerro-magnetic material affixed thereto. The shaft 93 is rotatablysupported by a support arm-97 which has a permanent magnet 96attachedthere- .to.-- A friction washer 95 is secured to the magnet andfrictionally engagesthe disc 94. The assembly including disc 94,shaft'93'and gear 92 will rotate only when the force applied to gear 92is not sufficient to overcome the resistance of the movable partsconnected thereto but is sufficient to overcome the frictionalresistance of the washer 95 so that disc 94 slips. The magnitude of thisfrictional resistance is determined by the coeflicient of friction be-,tween disc 94 and washer 95 and the pull exerted by the magnet 96 ondisc 94. When the worm screw 91 is turned during continuous tuning, theworm gear 92 does not rotate because the resistance of the carriage tomovement is very slight, so the teeth of gear 92 follow the threads ofworm screw 91 and the core carriage moves. When one of the pushbuttons29 is depressed, the force exerted through the worm gear 92 on the wormscrew 91 is not sufficient to turn it, but is suificient to overcome thefrictional force holding gear 93. Therefore, disc 94 slips .and gear 93rotates and walks along the threads -of worm screw 91. The support arm-97 is pivotally connected to a bracket 98 which is attached to the corecarriage 40, and a spring 99 biases the arm 97 to keep the teeth ofgear92 in full engagement with the threads of screw 91 so that there is noslippage and the corecarriage does not drift under vibration. It isapparent from the foregoing description that the tuner of the inventionis very compact and is easily operated. The efficient arrangement ofgears and clutch parts in the continuous tuning control mechanismcombined with the compact arrangement of the V-can'1sand key slidesprovides a tuner of considerably reduced size :as

,port, circuit means controlled by said carriage for selecting radiosignals of predetermined frequencies within a frequency range uponmovement of said carriage to predetermined tuning positions, saidcarriage havingja plurality of V-shaped cam surfaces, a plurality of keyslides movable linearly on said support perpendicular to the movement ofsaid carriage, means limiting-the movement of said key slides to apredetermined range of movement, said key slides each having a cammember thereon engageable with a corresponding one of said V-shaped camsurfaces to move said carriage to one of the predetermined tuningpositions thereof, means on said key slides to permit lateral movementof said cam members with respect to the associated key slides todifferent tuning control positions, and locking means carried on each ofsaid key slides and engageablewith said cam .members to lock the same inselected control positions, said key slides each having an actuatingmember movable with said key slide and relatively movable with respectto said key slide in a direction perpendicular to ,said carriage torelease and re-engage said locking means.

'2. A tuner for a radio receiver including in combination, a support, anelongated carriage movable longitu- Ldinally on's'aid support andincluding spaced parallel plates,

circuit means controlled by said carriage for selecting radio signals ofpredetermined frequencies within afrequency range upon movement of saidcarriage to.

predetermined tuning positions, a plurality of generally V-shaped camsurfaces on said plates of said carriage,

each-of said cam surfaces having predetermined curvature, a plurality ofkey slides disposed in parallel rows on said support and movablelinearly in a direction perpendicular to the movement of said carriage,said key slides each having a laterally adjustable cam member thereonengageable with a corresponding one of said V- shaped cam surfaces tomove said carriage to one of the predetermined tuning positions thereof,with the curvature of said cam surfaces controlling the pressurerequired to depress said key slides and move said carriage.

3. A tuner for a radio receiver including in combination, a support, acarriage movable linearly on said support, circuit means controlled bysaid carriage for selecting radio signals of predetermined frequencieswithin a frequency range upon movement of said carriage to predeterminedtuning positions, a plurality of V-shaped,

cams on said carriage, a plurality of key slides movable linearly onsaid support in a direction perpendicular to the movement of saidcarriage, said key slides each having a laterally adjustable cam memberthereon engageable with a corresponding one of said V-shaped cams tomove said carriage to one of the predetermined tuning positions thereof,said V-shaped cams having sides of predetermined curvature forcontrolling the effective force transmitted to said carriage accordingto the lateral position of said cam members with respect to saidV-shaped cams upon engagement therewith.

4. A tuner for a radio receiver including in combination, a support, acarriage movable linearly on said support, circuit means controlled bysaid carriage for selecting radio signals of predetermined frequencieswithin a frequency range upon movement of said carriage to predeterminedtuning positions, a plurality of V-shaped cam surfaces on said carriage,a plurality of key slides movable linearly on said support in adirection perpendicular to the movement of said carriage, said keyslides each f -i,ngv an actuating portionand an adjustablecammem-'berengageable with one of said V-shaped cam surfaces positions having apredetermined relation to the V-shaped cam surface associated therewithfor controlling the tun- .ing positions to which said carriage is movedupon actuation of said key slides, said key slides each havingquickrele'aselock means engaging and holding said adjustable cam membersin selected control positions, ,said vlock means being released uponpredetermined movement of said actuating portion away from said carriageand reengaged upon predetermined movement of ,said

actuating portion toward said carriage.

,5. A tuner for a radio receiver including in combination, a support, acarriage movable linearly on said support, circuit meanscontrolled bysaid carriage for selecting radio signals of predetermined frequencieswithin a .fre uency range upon movement of said carriage to redeterminedtuning'positions, a plurality of V-shaped cam surfaces on said carriageeach having sides of predetermined curvature, a plurality of key slidesmovable linearly on said support perpendicular to the movement of saidcarriage, said key slides each having an actuating portion and anadjustable vpin engageable with one 'of said cam surfaces to move saidcarriage to one ofthe predetermined tuning positions thereof, saidadjustable pins each being movable laterally on said key slides tovarious control positions having a predetermined relation to the camsurface associated therewith for controlling the tuning positions towhich said carriage is moved upon actuation of said key slides, said keyslides each having quick-release lock means for engaging and holdingsaid adjustable pins in selectedcontrol positions, said lock means beingheld against said pin by said actuating portion, and said lock meansreleasing said pin upon predetermined movement of said actuating portionaway from said carriage and re-engaging said pin upon predeterminedmovement of said actuating portion toward said carriage.

6. A tuner for use with a radio receiver to select radio signals ofpredetermined frequencies within a frequency range, including incombination, a support, a carriage movable linearly on said supportthrough arange of movement, circuit means controlled by said carriageaccording to the movement thereof for controlling the tuning of theradio receiver, a plurality of V-shaped cam surfaces on said carriage, aplurality of key slides movable linearly on said support perpendicularto the movement of said carriage, said key slides each having anadjust'able member thereon engageable with one of said V-shaped camsurfaces to move said carriage to a predetermined tuning position, saidadjustable members each being laterally movable with respect to saidkeyslides, quick-release lock means for holding each ofisaid adjustablemembers in a selected position and for releasing the same foradjustment, each of said adjustable members when in the releasedcondition being moved laterally by the associated V-shaped cam surfaceupon engagement therewith and riding said cam surface to a control position aligned with the base thereof upon depressing the associated keyslide, said lock means being operable upon further depression of saidkey slide to hold said adjustable member in said control position forsetting a corresponding tuning position for said carriage.

7. A tuner for a radio receiver including in combination, a support, acarriage movable linearly on said support, circuit means controlled bysaid carriage for selecting radio signals of predetermined frequencieswithin a frequency range upon movement of said carriage to predeterminedtuning positions, a plurality of V-shaped cam surfaces on said carriage,a plurality of key slides movable linearly on said support perpendicularto the move-' ment of said carriage, said key slides each having alaterincluding a lever supported on each of said key engageable with thepin thereof, each of said key slides tally movable pin thereonengageable with one of said cam surfaces to move said carriage to one ofthe predetermined tuning positions thereof, quick-release lock means forholding each of said pins in a selected position and v which saidcarriage is moved upon actuation of said key "slides.

8. A tuner for a radio receiver including in combination, a support, acarriage movable linearly on said support, circuit means controlled bysaid carriage for selecting radio signals of predetermined frequencieswithin a frequency range upon movement of said carriage'to predeterminedtuning positions, a plurality of V-shaped cam surfaces on said carriage,a plurality of key slides movable linearly on said support perpendicularto the movement of said carriage, said key slides each having anadjustable pin thereon engageable with one of said cam surfaces to movesaid carriage to one of the predetermined tuning positions thereof, saidkey slides including a slidable plate having an elongated slot thereinreceiv- -ing and guiding said pin,

a lock plate movable between first and second positions with respect tosaid slide plate and having an actuating portion thereon, and a leversupported on said slide plate and engageable with said pin to hold thesame against said slide plate,

said lock plate including a resilient portion engaging and applyingresilient pressure to said lever in said first position for locking saidpin and releasing said lever in said second position for permittingmovement of said lever to release said pin, said adjustable pins when inthe released condition being movable in said slots to various controlpositions having a predetermined relation to the V-shaped cam surfaceassociated therewith for controlling the tuning positions to which saidcarriage is moved upon actuation of said key slides.

9. A tuner for use with a radio receiver including in combination, asupport, a carriage movable linearly on said support through a range ofmovement, circuit means controlled by the movement of said carriage forselecting radio signals within a range of frequencies, a plurality ofV-shaped cam surfaces on said carriage, a plurality of movable memberseach having a portion engageable with one of said V-shaped cam surfacesupon movement of said movable member for moving said carriageto'predetermined tuning positions, continuous control means coupled to saidcarriage for moving the same through the range of movement thereof, saidcontinuous control means including a worm screw and a meshing worm gear,

friction clutch means coupling said worm gear to said carriage, anddriving means for rotating said worm screw, said clutch means includinga magnet, and a magnetic member coupled to said worm gear, with frictionmaterial between said magnet and said magnetic member frictionallyholding said magnetic member and said worm gear so that the meshingteeth thereof follow the threads of said worm screw for moving saidcarriage upon actuation of said driving means, and said carriage movingin response to actuation of said movable members and applying force tosaid magnetic member causing the same to slip so that said worm gearrotates and walks along said worm screw absorbing said force withouttransmitting the same.

10. A tuner for use with a radio receiver including in combination, asupport, a carriage movable linearly on said support through a range ofmovement, circuit means controlled by the movement of said carriage forselecting radio signals within a range of frequencies, a plurality ofmovable members each engageable with one of said V-shaped cam surfacesfor moving said carriage to predetermined tuning positions, continuouscontrol means coupled to said carriage for moving the same through therange of movement thereof, said continuous control means including aworm screw, a worm gear meshing with said worm screw and having a rotaryshaft afi'ixed thereto, friction clutch means coupling said worm gear tosaid carriage, said clutch means including a support arm pivotallyconnected to said carriage and supporting said shaft, a magnetic discaffixed to said shaft, a permanent magnet afiixed to said support armand attracting said magnetic disc, and friction material interposedbetween said disc and said magnet and engaging said disc for resistingrotation of said shaft and said gear, means biasing said pivotal supportarm for maintaining said worm gear in full tooth engagement with saidworm screw, and driving means for rotating said worm screw, saidmagnetic disc being held by said friction material and said magnet toprevent rotation of said worm gear upon actuation of said driving meansso that the teeth of said worm gear follow the threads of said wormscrew and apply force through said shaft to move said carriage, and saidcarriage moving in response to actuation of said movable members andapplying force to said shaft thereby causing said magnetic disc torotate and slip on said friction material so that said Worm gear rotatesand walks along said worm screw absorbing said force withouttransmitting the same.

References Cited in the file of this patent UNITED STATES PATENTS

